To obtain the subject monofilament having good tenacity and elongation, low hydrothermal and dry-heat shrinkage and excellent dimensional stability and moist-heat resistance and useful as industrial materials or the like by fiber manufacturing of a specified polyamide composition including a specified quantity of a carbodiimide compound.
This polyamide monofilament has ≥5.0 g/d tenacity, ≤5.0% dry heat shrinkage at 120°C, ≤10.0% hydrothermal shrinkage and ≥80% tenacity retention after hydrothermal treatment and is obtained by melt spinning of an polyamide composition including ≥60 wt.% poly(metaxylylene adipamide) and 0.1-2.0 wt.% carbodiimide compound such as N,N'-bis(2,6-diisopropylphenyl) carbodiimide, cooling the resultant thread, drawing at 60-3000°C by a factor of 4.0-7.0 and thermal treatment under 1.0-15.0% relaxation. It is preferable to include 20-18,000 ppm activated carbodiimide compound in the filament.
KANATSUKI AKIRA
YOKOYAMA HIROSHI
